[PATCH 3/3] KVM: arm64: Don't hold 'vm_table_lock' across guest page reclaim

[Will Deacon]

Now that the teardown of a VM cannot be finalised as long as a reference
is held on the VM, rework __pkvm_reclaim_dying_guest_page() to hold a
reference to the dying VM rather than take the global 'vm_table_lock'
during the reclaim operation.

Signed-off-by: Will Deacon <will at kernel.org>
---
 arch/arm64/kvm/hyp/nvhe/pkvm.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c
index b955da0e50bc..7ed96d64d611 100644
--- a/arch/arm64/kvm/hyp/nvhe/pkvm.c
+++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c
@@ -918,15 +918,16 @@ teardown_donated_memory(struct kvm_hyp_memcache *mc, void *addr, size_t size)
 
 int __pkvm_reclaim_dying_guest_page(pkvm_handle_t handle, u64 gfn)
 {
-	struct pkvm_hyp_vm *hyp_vm;
+	struct pkvm_hyp_vm *hyp_vm = get_pkvm_hyp_vm(handle);
 	int ret = -EINVAL;
 
-	hyp_spin_lock(&vm_table_lock);
-	hyp_vm = get_vm_by_handle(handle);
-	if (hyp_vm && hyp_vm->kvm.arch.pkvm.is_dying)
-		ret = __pkvm_host_reclaim_page_guest(gfn, hyp_vm);
-	hyp_spin_unlock(&vm_table_lock);
+	if (!hyp_vm)
+		return ret;
 
+	if (hyp_vm->kvm.arch.pkvm.is_dying)
+		ret = __pkvm_host_reclaim_page_guest(gfn, hyp_vm);
+
+	put_pkvm_hyp_vm(hyp_vm);
 	return ret;
 }
 
-- 
2.53.0.1118.gaef5881109-goog